You see that faith was active along with his works, and faith was completed by his works; (ESV)
Faith is not just a feeling. Faith is not a temporary thing. Faith is something that has an object, and as James tells us here in this verse, Faith has a destination. There are many people who say, "just have faith." Faith in what? As believers in Jesus Christ we know that our faith is in God, who purchased our salvation by the sacrifice of his son, Jesus Christ.
James is using an illustration from the Old Testament, talking about how Abraham showed his faith by works. In fact, he says, his faith was completed by his works. I want to focus on this idea that his faith was completed by his works. In other words, our faith has a destination. We have faith in God. Our faith is in something that is true, but is not yet seen. The day will come when our faith will be complete.
Abraham was a man who believed God and it was credited to him as righteousness. His faith was real. His faith was genuine. But as you continue to read the story of Abraham you find that his faith was demonstrated by work after work that he did in obedience to the Lord, who was the object of his faith. Abraham is now with the Lord. His faith, completed by his works, is finished.
There is a wonderful way that Jesus is described in the Book of Hebrews.
 looking to Jesus, the founder and perfecter of our faith, who for the joy that was set before him endured the cross, despising the shame, and is seated at the right hand of the throne of God. (ESV)
Jesus is the founder of our faith. Our works are not the founder of our faith. That faith that we have received from Jesus Christ is also completed, or finished, by Jesus himself. The works that we do that prove our faith to be genuine are works that we do in Christ Jesus. Ultimately, we will have our faith completed when we are in Heaven with the Savior, the author and finisher of our faith.
Celebrate the work that Jesus has done in you. You have received faith, you have walked in faith, you will finish the journey in faith. Jesus will see to it.